Foliar analysis and response of fertilized chlorotic Sitka spruce plantations on salal-dominated cedar–hemlock cutovers on Vancouver Island

1989 ◽  
Vol 19 (12) ◽  
pp. 1501-1511 ◽  
Author(s):  
G. F. Weetman ◽  
R. Fournier ◽  
J. Barker ◽  
E. Schnorbus-Panozzo ◽  
A. Germain

A series of microplot and conventional plot trials were used to determine the nutritional status and required nutrient additions to bring young chlorotic Sitka spruce (Piceasitchensis (Bong.) Carr) plantations out of "check." Check occurs on clear-cut and burned old-growth western red cedar (Thujaplicata Donn ex D. Don) and western hemlock (Tsugaheterophylla (Raf.) Sarg.) stands in the Coastal Western Hemlock biogeoclimatic zone growing on deep morhumus Podzols invaded by dense salal (Gaultheriashallon). Microplot trials identified the requirement for N and P. Checked trees responded to fertilization immediately with a 4- to 8-year temporary increase in leader length. Grubbing out of aboveground salal did not improve tree nutrition. There is a close parallel to "heather check" noted with Sitka spruce in British and Irish moorlands; a possible allelopathic effect of salal is suspected. It is concluded that one or more N and P additions are required to establish crown closure. Fertilized Sitka spruce show a high incidence of spruce weevil attack. The deficient and optimum foliar nutrient concentrations developed in Britain for the diagnosis of Sitka spruce appear to be applicable.

1995 ◽  
Vol 25 (1) ◽  
pp. 18-28 ◽  
Author(s):  
B.J. Hawkins ◽  
M. Davradou ◽  
D. Pier ◽  
R. Shortt

One-year-old seedlings of western red cedar (Thujapiicata Donn ex D.Don) and Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) were grown for one season in five nutrient treatments with nitrogen (N) supplied in solution at rates of 20, 100, or 250 mg•L−1 and phosphorus (P) supplied at rates of 4, 20, or 60 mg•L−1. Growth, onset of dormancy, frost hardiness on six dates, and foliar nutrient concentrations in autumn and spring were measured. Midwinter rates of net photosynthesis and transpiration were measured at air temperatures of 4, 7, and 11 °C in seedlings from all nutrient treatments. Recovery of net photosynthesis and transpiration in whole seedlings from the three N treatments was assessed at intervals for 28 days after the seedlings were frozen to −5, −15, and −25°C. Foliar N content differed significantly among nutrient treatments and was positively correlated with supply. Mitotic activity ceased earliest in plants with low N supply. Douglas-fir seedlings in the low-N treatment also ceased height growth earliest. These differences in growth had no significant correlation with frost hardiness. No consistent differences in frost hardiness among nutrient treatments were observed. Higher rates of N and P supply resulted in higher rates of winter net photosynthesis. Net photosynthesis was reduced dramatically by night frost, with greater damage occurring at lower temperatures. Net photosynthesis recovery occurred most quickly in seedlings with the midrate of N and P supply.


1993 ◽  
Vol 23 (4) ◽  
pp. 743-748 ◽  
Author(s):  
André J. Hudson

The natural invasion of mountain alder (Alnuscrispa (Ait.) Pursh) into monoculture plantations of black spruce (Piceamariana (Mill.) B.S.P.) and Sitka spruce (Piceasitchensis (Bong.) Carr.) afforded an opportunity to assess the effects of mountain alder on soils, and on the growth, nutrient status, and survival of spruce in eastern Newfoundland. The plantations were established on ploughed Kalmia–Vaccinium heath in 1968–1969. Significant increases in the growth of spruce were associated with the presence of high densities of mountain alder in the two plantations studied. The increases began 3–6 years after the invasion and establishment of mountain alder. Estimated nitrogen (N) contributions to each plantation from mountain alder leaf litter fall were approximately 50 kg•ha−1•year−1. Spruce foliage N content was 10–15% higher in high-density mountain alder (HD-alder) plots than in low-density mountain alder (LD-alder) plots, but other foliar nutrient concentrations were low and possibly deficient in the HD-alder plots. Development of a litter fall–humus layer was observed in HD-alder plots but not in LD-alder plots; however, B-horizon soil-N values did not differ significantly between HD-alder and LD-alder plots. The mountain alder invasion did not reduce the densities (stems/ha) of spruce. Additional studies on the autecology of Alnus spp. native to Newfoundland, and on alder-spruce interaction are recommended to further the development of an adequate ecological basis for heathland and peatland afforestation in the region.


1989 ◽  
Vol 19 (12) ◽  
pp. 1512-1520 ◽  
Author(s):  
G. F. Weetman ◽  
R. Fournier ◽  
J. Barker ◽  
E. Schnorbus-Panozzo

Microplot and conventional plot trials were used to determine the nutritional status and required nutrient additions to bring young regenerations of western hemlock (Tsuga heterophylla (Raf.) Sarg.) and western red cedar (Thujaplicata Donn ex D. Don) out of "check." The trees were growing on deep mor-humus Podzols invaded by dense salal (Gaultheriashallon). Salal removal by grubbing and application of Garlon was also tested. Foliar vector analysis, used for hemlock, identified a response to N and P that was confirmed by subsequent 3-year height growth response. Salal removal resulted in increased N uptake only in cedar. Cedar also responded to N and P additions, but vector analysis was not feasible owing to indeterminate growth. Foliar analysis values are compared with published data. It is suggested that salal competition or allelopathy may be the primary cause of inadequate N and P nutrition.


1990 ◽  
Vol 20 (6) ◽  
pp. 764-773 ◽  
Author(s):  
Constance A. Harrington ◽  
Charles A. Wierman

Seven silvicultural treatments were applied to a young (15- to 20-year-old), naturally regenerated western red cedar (Thujaplicata Donn ex D. Don) stand growing on a poor-quality site in western Washington. The treatments were as follows: unthinned, unfertilized (untreated); unthinned, fertilized with ammonium nitrate, dicalcium phosphate, and potassium sulfate; thinned, unfertilized; thinned, fertilized with urea; thinned, fertilized with ammonium nitrate; thinned, fertilized with ammonium nitrate and dicalcium phosphate; and thinned, fertilized with ammonium nitrate, dicalcium phosphate, and potassium sulfate. Elemental application rates were 300 kg nitrogen, 100 kg phosphorus, 129 kg calcium, 100 kg potassium, and 41 kg sulfur per hectare. Growth and foliar nutrient concentrations were monitored for 5 years. Five-year height growth and diameter growth of the 20 tallest trees per 0.08-ha measurement plot were both substantially greater in all thinned or fertilized treatments than in the unthinned, unfertilized treatment. The three best treatments for height growth (the treatments containing ammonium nitrate and dicalcium phosphate) had 65% more growth than the unthinned, unfertilized treatment. The two best treatments for diameter growth (thinned, fertilized with ammonium nitrate and dicalcium phosphate) had 106% more growth than the unthinned, unfertilized treatment. The effects of thinning alone were small compared with the effects of fertilization alone or fertilization combined with thinning. Initial foliar nitrogen concentrations showed that the site was nitrogen deficient, and both nitrogen sources, urea and ammonium nitrate, increased growth. The addition of dicalcium phosphate resulted in significantly greater incremental growth above that attributed to nitrogen alone, but the further addition of potassium sulfate did not increase growth significantly. Increases in foliar nitrogen and phosphorus associated with fertilization were still evident 5 years after treatment. All sizes of trees responded to treatment, and growth of the total stand followed the same trends as for the 20 tallest trees per plot. Basal area growth on an absolute basis was best in the unthinned, fertilized treatment (more than twice that of the unthinned, unfertilized treatment) and on a percent basis was best in the thinned treatment fertilized with ammonium nitrate, dicalcium phosphate, and potassium sulfate.


1996 ◽  
Vol 26 (2) ◽  
pp. 313-321 ◽  
Author(s):  
Scott X. Chang ◽  
Gordon F. Weetman ◽  
Caroline M. Preston ◽  
Kevin McCullough ◽  
John Barker

Fertilizer labeled with 15N was used to study the fate of N in forest soil–plant systems with (control) and without competition (treated) from an ericaceous evergreen shrub, salal (Gaultheriashallon Pursh), on a western red cedar (Thujaplicata Donn ex D. Don)–western hemlock (Tsugaheterophylla (Raf.) Sarg.) clear-cut site on northern Vancouver Island. Fertilizer was applied in April 1991 at 200 kg N•ha−1 as (NH4)2SO4 (3.38044% 15N enrichment) to single-tree plots of 1 m radius. Four-year-old western red cedar, western hemlock, and Sitka spruce (Piceasitchensis (Bong.) Carrière) were used and the plots were destructively sampled after two growing seasons (October 1992). The distribution of 15N within trees was virtually unaffected by the treatment but displayed differences among species. The majority of the 15N in a tree was found in the current-year needles. Because of the dilution effect, 15N abundances in the above ground tree components were not different between treatments but 15N contents were significantly increased by salal removal. The pattern of and treatment effect on total N distribution were similar to those of 15N. Total recovery by trees of applied 15N was 7.7, 17.8, and 10.3% in the treated plots planted with cedar, hemlock, and spruce, respectively. The corresponding values for the control plots were 4.1, 2.0, and 4.9%. Understory in the control plots immobilized 14.8, 24.6, and 13.5% of the applied N for plots planted with the respective species. Total recoveries in soil and vegetation ranged from 57 to 87%, of which 59 to 82% was recovered in the soil compartments. Results clearly showed that trees competed poorly with the understory vegetation for the applied fertilizer N.


1977 ◽  
Vol 55 (2) ◽  
pp. 405-414 ◽  
Author(s):  
T. J. D. VanderSar ◽  
J. H. Borden

Both sexes of prewintering P. strobi adults preferred to feed on Sitka spruce lateral branch sections of larger diameter when presented a choice of two sections from the same current-year host lateral. In choice bioassays, both sexes preferred to feed on Sitka spruce rather than western hemlock or western red cedar. Females preferred to feed on Sitka spruce rather than Douglas-fir, whereas males did not discriminate. When presented either Sitka spruce or one of the three nonhost species alone, both sexes fed equally on Sitka spruce, Douglas-fir, and western hemlock. Neither sex fed on western red cedar, and weevils were seldom observed in contact with this species. Both sexes preferred to feed on Sitka spruce sections soaked in water rather than on those soaked in cedar exudate, suggesting that cedar contains repellents and (or) feeding deterrents. Sustained feeding by both sexes on pith discs containing a 50% ethanol extract of Sitka spruce leader bark suggests that Sitka spruce bark contains feeding stimulants. As only female P. strobi exhibit a feeding response that is dependent on the concentration of applied extract, females may have a more prominent role than males in host-tree selection during spring dispersal.


1986 ◽  
Vol 16 (3) ◽  
pp. 642-647 ◽  
Author(s):  
Thomas P. Sullivan ◽  
William T. Jackson ◽  
James Pojar ◽  
Allen Banner

This study measured the incidence of feeding damage by porcupines (Erethizondorsatum Allen) within the second-growth western hemlock (Tsugaheterophylla Raf. (Sarg.)) – Sitka spruce (Piceasitchensis (Bong.) Carr.) forest of Khutzeymateen Inlet, 45 km northeast of Prince Rupert, British Columbia. Tree mensuration and damage assessments were conducted in 69 sample plots located on four transects. Western hemlock, which composed 67% of sampled stands, was the most severely (52.7% of trees, of which 5.1% were newly attacked) damaged species followed by Sitka spruce with minor (7.8%) damage. The less frequent amabilis fir (Abiesamabilis (Dougl.) Forbes) and western red cedar Thujaplicata Donn.) were not attacked. The total percentage of girdled (mortality) hemlock stems was 30.9%. Hemlock trees with a dbh > 27.4 cm had 55.9% of stems girdled. Porcupines attacked and girdled a significantly greater proportion of large than small diameter hemlock trees. Stems smaller than 125.5 cm dbh had little (3.7%) damage. Significantly more damage wounds were recorded in the middle and upper thirds of hemlock stems than in the lower bole. Dominant and codominant hemlock were preferred by porcupines in their feeding attacks. In combination with porcupine control measures, these stands clearly require some form of silvicultural treatment, such as sanitation spacing, conducted initially as an operational trial on at least a 20-ha block.


1990 ◽  
Vol 20 (6) ◽  
pp. 712-721 ◽  
Author(s):  
Susan L. Borchers ◽  
David A. Perry

A greenhouse bioassay was used to compare the growth, ectomycorrhiza formation, and foliar nutrient concentrations of Douglas-fir seedlings grown in soils collected at different distances from hardwood species. Soil nutrient concentrations and bulk densities were also determined. The soils were collected from two southwestern Oregon sites that had been clear-cut and broadcast burned 5 years previously. The sites, poorly stocked with conifer reproduction, were occupied primarily by grasses, forbs, and scattered individuals of tanoak (Lithocarpusdensiflora (Hook. & Arn.) Rehd.), Pacific madrone (Arbutusmenziesii Pursh), and canyon line oak (Quercuschrysolepis Liebm.). Five-month-old seedlings grown in media containing mineral soil collected beneath hardwood crowns had on average 60% greater height, 2.2 times greater weight (roots plus shoots), and almost 2 times more total and ectomycorrhizal short roots than seedlings grown in media containing soil collected more than 4 m from a hardwood. Rhizopogon sp. and Cenococcumgeophilum dominated on seedlings grown in hardwood soils, and an unidentified brown ectomycorrhiza dominated on seedlings grown in open area soils. The effect of hardwoods did not vary among the three hardwood species or between the two sites. A study of soils collected at various distances from hardwoods indicated that the effect extended between 2 and 3 m. Average foliar nitrogen was higher for seedlings grown in hardwood area than in open area soils, but differences were not statistically significant. Differences in other foliar nutrients of seedlings grown on soils from beneath the three hardwood species were inconsistent. Differences in soil nutrient concentrations were also inconsistent; however, rates of mineralizable nitrogen (anaerobic) were from 2 to nearly 6 times higher in hardwood area than open area soils, and soil pH was higher. Results suggest that the pioneering hardwoods strongly influence soil biological activity in these clear-cuts and impose one or more soil patterns that favor establishment and growth of conifer seedlings.


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